Lubricating composition



March 4, 1952 R. OHALLORAN LUBRICATING COMPOSITION Filed Feb. 2, 19500mm. 0mm., O`m. 0mm Ohm 0mm Omlw Obw OQ O Om` OQ o" om on ,m

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A00mn e. O'Aledmwvem/Zvw 53521-1 Mmm? Patented Mar. 4, 1 952 UNITEDSTATES PATENT OFFICE LUBRICATING COMPOSITION Rosemary OHalloran,Elizabeth, N. J., assignor to Standard Oil Development Company, acorporation of Delaware Application February 2, 1950, Serial No. 142,014

6 Claims. (Cl. 252-40) l 2 This invention relates to a lubricatingcomweight fatty acids and a sodium salt of a low position suitable foruse as an all-purpose lubrimolecular weight organic acid. These:attempts cant. More particularly, this invention relates have failed,however, due to the coprecipitation to a lubricating grease which iscompounded by of the high and low molecular weight soaps in blendingseparate grease components to form a 5 the high viscosity index oil.Ihis failure of disgrease having excellent lubricating properties atpersion is probably due to the incompatability of both high and lowtemperatures. the complex soap containing low molecular It is known inthe art that grease compositions weight organic acid salts and the highviscosity which are made by incorporating into a lubricatindex oils attemperatures necessary for grease ing oil the desired amount of thesodium salt formation.

of a low molecular Weight acid in addition to the It has now been foundand forms the subject sodium soap of a higher molecular weight fatty ofthis invention that a grease composition in acid, have desirableproperties that make them corporating the desirable characteristics ofthe operable as lubricants for many purposes. For soda greases and themixed soda-barium greases instance, these soda greases have excellentlubrimay be made by a process of cold blending. eating qualities at hightemperatures and out- Broadly speaking, the grease compositions of thisstanding shear stability characteristics. Their invention are composedof two components. dropping points are very high and they show Component1 is a soda-barium grease and comexcellent oxidation resistance and oilseparation ponent 2 is a grease containing the sodium soap qualities. Insome respects, however, these soda of a high molecular weightsubstantially satugreases are undesirable for an all-purpose lubriratedfatty acid and the sodium salt of a low cant. The high soap contentnecessary to give molecular weight organic acid. The two grease them thedesirable structural stability and shear, components are made separatelyand then breakdown resistance results in an excessively blended togetherat room temperatures by the hard grease which does not soften when usedfor use of a suitable homogenizer or grease mill. It

lubricating industrial machinery, resulting in is felt that thissuccessful blend is due to the undersirably noisy operation. At lowtemperasimilarity of the two component greases, both tures, these sodagreases fail to give satisfactory being substantially soda-soap-fattyacid greases. lubrication because of their high soap content and This isborne out by the fact that component 2 also because they can not be madeusing a lubriadmixed with a calcium or lithium base grease cating oilhaving a low rate of viscosity change results in a fluid mixture as doescomponent 1 with temperature, a desirable dispersing medium admixed-with a soda-soap-rapeseed oil grease.

for low temperature greases. Apparently the soap Component 1 may bedescribed generally as complex formed between the high and low mobeing agrease formed by dispersing into a delecular weight salts is excessivelyinsoluble in a sii-able lubricating oil a mixture of the sodiumparaifinic mineral oil. and barium soaps of any of the commonly known Itis also known that greases prepared by dissoap forming materials. Theviscosity index of persing a mixed soda-barium or soda-strontium the oilchosen should be high enough 'to give the soap of a high molecularweight fatty acid in a desired low temperature properties to thefinished lubricating oil of high viscosity index, that is a 40 grease.Oils having a viscosity index above about viscosity index above about'75, have desirable low 75 are especially desirable. A partial list ofthe temperature lubrication characteristics and asoft soap formingmaterials would include hydrostructure which makes them of general usein ingcnated sh oil acids, stearic acid, oleic acid, dustriallubrication. These mixed soda-barium hydroxy stearic acid, beef fat,tallow, or mixtures or soda-strontium soaps are easily dispersible in ,5of the above in any proportion. In the instant a lubricating oil havingthe desirable low rate of invention, the preferred embodimentcontemchange of viscosity with temperature and thus plates asodium-barium soap of hydrogenated fish have good lubricating propertiesat low temperaoil acids.

tures. These mixed base greases, however, have The mol ratio of thesodium soap to the barium the disadvantage of being only fair instructure soap operable in the finished grease may vary stabilitygenerally and in some formulations havfrom 1:1 to 25:1. The preferredratio of sodium ing a relatively low dropping point. soap to barium soapis about 18:1. The amount It would be desirable to incorporate the adofthe mixture of soaps to be incorporated into vantages and properties ofthese two types of the desired lubricating oil to form component lgreases to obtain a soft, shear stable grease havwill depend upon thehardness of the nal grease ing a high dropping point, good oxidationstability composition that is desired, since increasing the andfurnishing satisfactory lubrication at both amount of soap in the greaseincreases the hardhigh and low temperatures. ness of the composition. Anoperable range Attempts have been made to form such a grease would befrom 5% to 50% total soap content, by incorporating directly into alubricating oil 5% to 20% being preferred. having a high viscosity indexthe desired amounts As to component 2, this ingredient is comprised ofthe sodium and barium soaps of high molecular of a mineral oil thickenedto a grease consistency Cil , 3 with a mixture of asodium soap of a highmo-v a lecular Weight fatty'acid'and a sodium salt of a low molecularWeightI organic acid. The sodium soap may be formed from any of the soapforming materials listed above, hydrogenatedsh oil acids being againpreferred. The W molecular Weight organic acid toform vthe sodium y saltmay be selected from such acids as acetic,Y acrylic, furoic, or any ofthe other structure improving loW molecular Weight organic acids. In 1the preferred embodiment, sodium furoate is used.

The mol ratio of the sodium soap to the sodium sale may vary from 1:1 to4:1 with mol ratios approaching `1-:1 beingpreferred..--

In blending thev gi ease components-of this in l.

ventionyit is preferred to use -frorn190% lto 65% f EXAMPLE IA Component1 In va mineral v-oil blendha'vingl a viscosity indexl-of-QZandaviscosity'at 210 F. of 41.9 S. U. S. there was'dispersed"about'16.5%of a mixtureof thesodium and barium'soapsof a hydrogena-ted sh'oil acid:Tl'rel ratio of thefsodium soap `to the barium soapwashlzl.- 'This`grease Was prepared in the usual'manner by heating the ingredients to atemperature of about 40021?. andfthen-pan;

coolingthe heated mixture-to room temperature, i3.

followed by cold'working of Athe grease cake Vto the desired penetrationlevel."

Component 2,

Byvtheproceduredescribed in a copending application, Serial No. 60,615,now United States Patent No, 2,516,137, issued July 25,V 1950, afurfural grease wasv preparedrby reacting 10% furfural into a furoicacid soap byl the Cannizzaro l, reaction. This soap was combined with ofa sodium soapY of hydrogenated fish oil acid and the mixture wasaddedfto a distillate having a viscosity index of about v60 and aviscosity at 210 F. of 36 S. U. S. The mixture of soap and oil washeated to atemperature of about 400 F. With stirringrand was thenpan-cooled to room temperature,-followed by cold Working.

Blemt` '75% of thesoda `barium grease and 25% of the furfural grease wasWorke`cl=5,000strokes with the'ASTM iineholefvvorker- (325 holes ,-lgindiameter). After this homogenization, a dark 'transparent grease ofexcellent appearance and structure resulted.

The properties of this cold blended grease in comparisons with component1 alone are shown in Table I below:

TABLE I Properties of Sodium- Cold Blended Barium Grease BasePenetration, mm./10, strokes 288r 295,` Wokcd lafter-60,000 strokes(finehole` 286` 359 p ate ASTM Dropping Point, F v 403 330 Tosrque -40F.Sec/Rev. (AN-G-l l 8.9

DEC .w y Oil Separation, Per Cent 50 Hrs/210 F 1.7` 6. 3 Water-Wash, PerCent Loss@ 77 F. 0 0 (AN-G-5a Spec) y N orma-Hoffman Oxidation Test,Hrs. to 50G-|- v 212 5 p. s.i. rop.14m ABEG-NLGl High Speed Spindle,Hrs. y 675 Y 549 250 F. and 10,000 R. P. M.

Inspection` of therdata set forth in Table I shows that theexperimentalV grease blend has properties markedly superior to those ofthe' sodium-barium grease which comprises of the blend. The penetrationof therblend. has remained unchanged after'long Working, while that ofthe base softened 64 mm./10. Thel dropping point, oil separation,andNorma-Hmalnbomb oxidation are yalsomimproved. Whilev the highspeedspindle life of the grease at 25061;. is im4 proved somewhatV (23%)by the incorporation of 4the furoate grease, subsequent experimentationhas shown that optimum spindleflife vis ob-i a grease containing 23.2%sodium soaps. -f The sodium furoate (7%) was introducedl into the greaseas suchor Was-produced in thegrease by the Cannizzaro reaction.-

the soda'bariumsoap in component 1 and these products are compared Withconventional sodaf lime -industrial greases containing 21% and-15% soaprespectively.

TABLE II "f INDUSTRIAL GREAsEBLNDs 75% Sodium/Barium Grease-F25Sodium-Fumare Grease Total Worked PertrationLinmJlO Fine n Percent 10.3323 342 344 349 423 10. 0y PaVSSm-- Y Y 23 11.8 294 317 318 322 Y 417* y5.3 d0 13 13. 3 282 284 300 301 406 3. 6 -d0 10 Conventional Na/CaGreases:

21% Na/Ca Soap 326 875 350 5. 6 Fail. 73 13.5% Na/Ca Soap 420+ 345 21. 7...do

l Penetration taken' immediately after working.

TheseA differentiV grades are shown containing 6%, 8% and 10% 0f points,better oil separation characteristics and better high temperatureperformance properties as measured by the wheel bearing test and the B.E. C. test than do the conventional industrial greases. Especiallynotable are the shear stability characteristics, the blend of greasesbreaking down only 20 to 30 penetration points during 10,000 strokeswith the ne hole worker.

To obtain comparative data as to the pressureviscosity relationship ofthe greases of this invention and the straight sodium-barium soapgreases, the grease blend of Example I and component 11 were subjectedto the standard pressure viscosity test. In this procedure, the greaseswere placed in a hydraulic-actuated grease cylinder tted with an orificecalibrated to give a rate of shear of 100 sec-1. The force required tomaintain a constant rate of flow at different temperatures was recorded,the amount of force required being indicative primarily of the viscosityof the grease at the test temperature.

The accompanying drawing represents the pressure viscosity curves ofthese two greases and indicates their structural changes over a widerange of temperatures.

The observed changes in structure of the blend at temperatures in theneighborhood of 300 F. explain why the grease compositions of thisinvention can not be made by conventional methods. It is to be seen attemperatures below 300 F. the blended grease composition has a structureof essentially the same plasticity as the sodiumbarium grease whileshowing improved properties of shear stability oxidation resistance, oilseparation, high temperature performance, etc. as discussed above. Thesharp continued increase of the viscosity of the blended grease attemperatures in excess of 300 F. shows the incompatibility of the lowmolecular weight salt with the p-arainic mineral oil and depicts theundesirable thickening effect of the mixture. The

change of structure of the blend at temperatures in the neighborhood of300 F. may also be observed by the increasing amounts of hard granularundispersed material in the grease mixture. At temperatures in theneighborhood of 300 F. the high and low molecular weight soapsapparently form a complex which will not disperse in a paralnic mineraloil having a high Viscosity index.

The grease blends of this invention are perfectly compatible with thecommonly used addi- -tive materials such as oxidation inhibitors, pourdepressors, viscosity index improvers, anti-corrosion agents, and thelike.

In summation, this invention is directed toward an improved lubricatingcomposition which is capable of furnishing desirable lubricationproperties at both high and low temperatures. It is also directed towarda method of incorporating into a parafnic mineral oil having a low rateo-f change of viscosity with temperature, a salt of a low molecularweight organic acid. It is particularly concerned with an improvedgrease composition which comprises a blended grease formed from asodium-barium grease and a sodium grease containing a sodium salt of alow molecular weight organic acid.

What is claimed is:

1. A blended grease composition which consists essentially of a mixtureof two component greases, one component being from 95% to 50% by weightbased on the weight of the total composition of a grease formed from amixture of the sodium and barium soaps of a high molecular weightsubstantially saturated fatty acid, the mol ratio of the sodium soap tothe barium soap being from 1 to 1 to 25 to l, and the other componentbeing from 5% to 50% by weight based on the weight of the totalcomposition of a grease formed from a mixture of the sodium soap of ahigh molecular weight substantially saturated fatty acid and the sodiumsalt of a low molecular weight organic carboxylic acid, the mol ratio ofthe soap and salt being from 1 to 1 to 4 to 1.

2. A blended grease composition which consists essentially of a blend oftwo comp-onent greases, one component being formed by dispersing in aparaflinic mineral oil having a high viscosity index a mixture of thesodium and barium soaps of a high molecular weight substantiallysaturated fatty acid, the mol ratio of said mixture of soaps beingwithin a range of from 1:1 to 25:1 and the other component being agrease composition formed by dispersing in a mineral lubricating oil asodium soap of a high molecular weight substantially saturated fattyacid and a sodium salt of a low molecular weight organic carboxylicacid, the mol ratio of the sodium soap to the sodium salt being within arange of from 1:1 to 4:1, said blend consisting essentially of from to65% by weight of the first com- Ap-onent and from 10% to 35% by weightof the second component.

3. A grease composition according to claim 2 wherein the high molecularweight substantially saturated fatty acid is a hydrogenated fish oilacid and the sodium salt of the low molecular weight organic acid issodium furoate.

4. A lubricating composition according to claim 2 wherein said firstcomponent consists essentially of from 5% to 50% of a mixture of sodiumand barium soaps dispersed in a parafnic type mineral oil, the ratio ofsaid sodium soap to said barium soap being 18:1 to 8:1 and the mol ratioof the sodium soap to the sodium salt of said second component beingwithin a range of from 4:1 to 1:1.

5. A method of preparing a lubricating grease compositi-on havingdesirable lubricating characteristics at both high and low temperatureswhich comprises preforming a grease from a mixture of the sodium andbarium soaps of a high 'molecular weight substantially saturated fattyacid, the mol ratio of the sodium soap to the barium soap being from 1to 1 to 25 to 1, preforming a second grease composition from a mixtureof the sodium soap of a high molecular weight substantially saturatedfatty acid and the sodium salt of a low molecular weight organiccarboxylic acid, and thereafter cold blending from 90% to 65% by weightof theiirst grease composition with from 10% to 35% by weight of thesecond grease composition.

6. A method of preparing a grease composition having desirablelubricating characteristics at both high and low temperatures whichcomprises preforming a grease composition by dispersing in a mineral oilhaving a high viscosity index a mixture of the sodium and barium soapsof a high molecular weight substantially saturated fatty acid, the molratio of said sodium soap to said barium soap being within a range offrom 1 to 1 to 25 to 1, ,preforming a second grease composition bydispersing in a mineral oil a mixture of the sodium soap of a. highmolecular weight sub

1. A BLENED GREASE COMPOSITION WHICH CONSISTS ESSENTIALLY OF A MIXTUREOF TWO COMPONENT GREASES, ONE COMPONENT BEING FROM 95% TO 50% BY WEIGHTBASED ON THE WEIGHT OF THE TOTAL CONPOSITION OF A GREASE FORMED FROM AMIXTURE OF THE SODIUM AND BARIUM SOAPS OF A HIGH MOLECULAR WEIGHTSUBSTANTIALLY SATURATED FATTY ACID, THE MOL RATIO OF THE SODIUM SOAP TOTHE BARIUM SOAP BEING FROM 1 TO 1 TO 25 TO 1, AND THE OTHER COMPONENTBEING FROM 5% TO 50% BY WEIGHT BASED ONTHE WEIGHT OF THE TOTALCOMPOSITION OF A GREASE FORMED FROM A MIXTURE OF THE SODIUM SOAP OF AHIGH MOLECULAR WEIGHT SUBSTANTIALLY